The importance of free-space optical (FSO) communication has increased during the last decade, introducing its unique features such as its high data rate, license-free spectrum, ease of deployability, and low power co...
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The importance of free-space optical (FSO) communication has increased during the last decade, introducing its unique features such as its high data rate, license-free spectrum, ease of deployability, and low power consumption. In the future, communication between low earth orbit (LEO) and geostationary earth orbit (GEO) satellites will be commonly established by using intersatellite optical wireless communication (IsOWC) systems. That enables GEO satellites to relay information to and from LEO satellites and fixed Earth stations that otherwise cannot transmit/receive data permanently. IsOWC systems are the most effective application of the FSO, and they will be favorited shortly because of their features. In this work, we established an IsOWC between GEO and LEO satellites at a distance of 45000 km to achieve a target bit error rate (BER) equal to 10(-6). Furthermore, we proposed an IsOWC system with suitable operating wavelengths. Physical techniques such as the multi-input multi-output(MIMO) technique and a wave division multiplexing (WDM) technique are employed.
This paper deals with the modelling and analysis of six degree of freedom random vibration test. It involves an advanced multi-input multi-output random vibration test system where three translational and three rotati...
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This paper deals with the modelling and analysis of six degree of freedom random vibration test. It involves an advanced multi-input multi-output random vibration test system where three translational and three rotational motions can be controlled simultaneously. In this work, a mechanical model of the six degree of freedom vibration test system is established such that eight exciters are modelled as spring damper pairs and the shaker table is assumed to be rigid. The acceleration properties of the test article undergoing such six degree of freedom base vibrations are analyzed and the relationships among the absolute acceleration, relative acceleration and base acceleration are derived. In practical applica-tions, typically there is no available angular acceleration sensor for high frequency measurements. Therefore, the three rotational accelerations are obtained from measured translational accelerations of three or more control sensors with a response coordinate transformation matrix. It is shown that the locations of the control points have a significant influence on the response spectral results, which is reflected in the condition number of the output coordinate transformation matrix. The general multi-input multi-output random vibration control method is applied to the 6-DOF random vibration test. A six degree of freedom random vibration test simulation is finally provided. (c) 2020 Elsevier Ltd. All rights reserved.
Orbital angular momentum technology (OAM), as one of the potential technologies of the next generation mobile communication system, has become a hot research point in recent years. OAM technology uses mode multiplexin...
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ISBN:
(纸本)9781728187556
Orbital angular momentum technology (OAM), as one of the potential technologies of the next generation mobile communication system, has become a hot research point in recent years. OAM technology uses mode multiplexing, which starts another dimension of multiplexing technology and can further improve spectrum efficiency. In this paper, we use the characteristics of OAM coaxial propagation to study the problem of user pairing in the same direction. Simulations show that using OAM for user pairing can significantly increase the number of pairing points compared with multi-input multi-output (MIMO) system. In addition, our scheme can obtain a obvious pairing gain at the specific location.
This paper investigates the physical-layer security attained by Receive Spatial Modulation (RSM) scheme against potential eavesdroppers. The impact of the involved parameters on the bit error rate (BER) at the legitim...
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ISBN:
(纸本)9781728163390
This paper investigates the physical-layer security attained by Receive Spatial Modulation (RSM) scheme against potential eavesdroppers. The impact of the involved parameters on the bit error rate (BER) at the legitimate receiver and the considered eavesdropper is shown and discussed. Moreover, a hybrid scheme is proposed in order to alleviate the impact of the channel estimation errors on the achievable BER at the legitimate receiver. The proposed scheme allows the transmitter to switch between RSM and the conventional SM based on the phase of the estimated channel coefficient. Simulation results reveal that the proposed scheme can achieve at least 3 dB SNR gain as compared to the RSM, while keeping the error rate at the eavesdropper within acceptable bound.
This article presents a deca-band multi-input multi-output (MIMO) antenna for full-screen metal frame smartphone, which covers wideband of GSM850, GSM900, DCS, PCS, UMTS, LTE2300, LTE2500, WLAN/WiMAX, N78, and sub-6 G...
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This article presents a deca-band multi-input multi-output (MIMO) antenna for full-screen metal frame smartphone, which covers wideband of GSM850, GSM900, DCS, PCS, UMTS, LTE2300, LTE2500, WLAN/WiMAX, N78, and sub-6 GHz (4.8-5.1 GHz) bands table. Two kinds of antenna structures are positioned on the long side edge and form two 2 x 2 MIMO array, covering the low-band (824-960 MHz) and mid-band (1710-2690 MHz/3300-3800 MHz), respectively. Four slot antennas are distributed on both sides of the short side edge. Each slot is connected to an antenna structure on the long side edge, sharing one port to form the high-band structure. By reutilization the low and mid-band structures, the high-band structure can achieved a wide band bandwidth without any additional matching structures. The high-band structure is composed of 4 x 4 MIMO array and covers the band of 4800-5825 MHz. A prototype of the proposed MIMO antenna is fabricated and measured. The isolation of the antenna is larger than 15 dB, the efficiencies are between 31% and 63%, and the ECCs is less than 0.3, which shows that the proposed antenna has great potential in the future 4G/5G smartphone application.
In this study, a 4x4 MIMO antenna box design consisting of antenna designs by using planar metal (Aluminum) plate and substrate (FR-4) used traditionally is presented to be used in smart home white good applications. ...
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In this article, an extension of the ℒ1adaptive control design is introduced for a class of non-affine multi-input multi-output nonlinear systems with unknown dynamics and unmeasured states. The system dynamics is rep...
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In this article, an extension of the ℒ1adaptive control design is introduced for a class of non-affine multi-input multi-output nonlinear systems with unknown dynamics and unmeasured states. The system dynamics is represented in the normal form with the bounded-input-bounded-output internal dynamics. At first, a stable virtual reference counterpart is constructed. Thereafter, a piece-wise continuous adaptive law is introduced to the actual system along with a low-pass filtered control signal that allows for achieving arbitrarily close tracking of the input and the output signals of the reference system. Rigorous mathematical proof is provided, and the theoretical results are verified with the simulation. [ABSTRACT FROM AUTHOR]
In the communication system,how to improve the system channel capacity has been a key research ***(multiple-inputmultiple-output) technology can greatly improve the channel *** combination of MIMO technology and UWB(...
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In the communication system,how to improve the system channel capacity has been a key research ***(multiple-inputmultiple-output) technology can greatly improve the channel *** combination of MIMO technology and UWB(Ultra-wideband) wireless communication technology forms a UWB-MIMO *** this paper,the UWB system,MIMO system,and UWB-MIMO system are mainly taken as the research objects,and whether the channel capacity of UWB-MIMO system is improved compared with MIMO and UWB wireless communication technology is *** channel capacity of the three technologies is obtained by formula calculation,and the corresponding results are obtained by comparison.
A novel peak-to-average power ratio (PAPR) reduction scheme designated as extended selected mapping (eSLM) is proposed for space-frequency block coding (SFBC) multi-input multi-output orthogonal frequency division mul...
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A novel peak-to-average power ratio (PAPR) reduction scheme designated as extended selected mapping (eSLM) is proposed for space-frequency block coding (SFBC) multi-input multi-output orthogonal frequency division multiplexing systems. In the eSLM method, extension matrices comprising amplitude extensions and phase rotations are constructed to indicate the selected signal index without the need for side information and to minimize the PAPR, respectively. To reduce the computational complexity incurred by the inverse discrete Fourier transform operation in generating the candidate signals, a low-complexity eSLM scheme (LC-eSLM) is developed by constructing equivalent candidate signals in the time domain. Notably, the extension matrices in both schemes preserve the orthogonality of the SFBC code, thereby facilitating low-complexity decoding. The simulation results show that the proposed eSLM scheme not only outperforms existing blind SLM-based methods. Compared with the costly ordinary SLM scheme, the eSLM scheme has a lower computational complexity with a performance loss of less than 0.3 dB and requires no side information. Furthermore, the computational complexity of the LC-eSLM scheme is around 40%-50% lower than that of the eSLM scheme with only a marginal degradation in the PAPR reduction performance.
Power line communications (PLCs) enable new and flexible networking functions in smart grids. However, due to the high attenuation and interference, it is a great challenge for PLC to achieve reliable and high data ra...
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Power line communications (PLCs) enable new and flexible networking functions in smart grids. However, due to the high attenuation and interference, it is a great challenge for PLC to achieve reliable and high data rate transmissions. Thus, we propose a multiple-inputmultiple-output (MIMO) architecture to improve the reliability and data rate for PLC networks. In viewing the data rate requirements of in-home PLC network systems, we develop a precoding scheme to maximize the system throughput. In harmonizing to the proposed precoding scheme, the closed-form of the sum data rate of the PLC-MIMO channel is derived. To improve the communication reliability, we propose a partial transmission sequence (PTS) based algorithm to mitigate the noise in PLC channels. The closed-form of the symbol error rate (SER) is derived according to the probability density function of the impulsive noise in PLC channels. Simulation results demonstrate that the proposed precoding scheme achieves a better throughput when compared to the conventional precoding schemes. Furthermore, the PTS-based noise mitigation algorithm significantly improves the SER performance of PLC links.
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